Switch.



' No'. 846,764. PATENTED MAR. 12, 1907.

W. R.'THOMPSON. SWITCH.

APPLIUATION FILED APR. 21, 1906.

by I UNITED srATEs PATENT OFFICE.

WILLIAM R. THOMPSON, or SOUTH 'NoRwALK, CONNECTICU*1,-ASSIGNOR Specification of Letters Patent.

' .OF ONE-HALFTO KIXG'W. MANSFIELD, OF NORWALK, CONNECTICUT.

' swn' oHc" Patented March 12, 1907.

Application filed April' 21, 1906. serial No 312,952. 7

Tamil whom in/(Ly concern 7 Be it known that I, VILLIA'M R. THOMP- SON, a cit zen of the Un ted States, residing at South Norwalk, Connecticut,-hav e invented certain new and useful, Improvements in Switches, of wlnch the following 1s;a clear,

. full, and exact descriptionf and, further-, to enable a definite length of time to elapse independent of the s eed of the car betweenthe making and brea 'ng of the switch-contact,

In electrically operating signals by means Of-electrical contact-strips electrically con-- I trolled or by means ofj aswitch mechanically T controlled by a moving part of a car,such as the trolley-wheel, great trouble is encountered in securing an actuated device which will have a substantially uniform time of contact for operation of the' signals independent of the speed of the car. 'If the contact is short, a rapidly-moving car will hardly affect the mechanism. If the contact is long, there is great danger of a car standing on the contact and keeping the signal operated. Thereis also found great trouble in preventing operation by a car moving in the opposite direction,

which may sometimes be a car backing on its. own track. It is to obviate these difliculties that I have devised the mechanism of this invention, which-accomplishes all these de'-- sired purposes in the device herein shown through the aid of a fluid-pressure apparatus; but obviously it is not essential that the device be fluid-operated. I prefer tovsecure this result by a mechanical fluid-operated device consisting, preferably, of a pneumatic transmitting device between the operatingarm and switch. This preferred device resembles closely the ordinary pneumatic gun, in which the projectile has its place taken by a switch-arm or plunger which is preferably so designed asnever to leave its cylinder.

The operating plunger of the device, like the pneumatic gun, is preferably held inward in its cylinder by strong springs, while achain secured to the plunger and to the operatinglever serves to draw the plunger out. ,I'prefer that the chamber forthe plunger be of greater volume and diameter than the chamher for the switch rod orplunger, so that a short s'low fi otion of theplunger will rapidly throw the rod out into engagement and keep it there for an appreciable moment. I pre-v fer to provide a restricted throttle-outlet to the cylinder todetermine the length of such contact, governing the time of motion like a dash-pot. I also provide an automatic letoff valve for operation toward and preferably at the end of thestroke of the plungerlfor opening the intercommunicating cylinders to the outer air, so'as'to allow certain springs to rapidly retract the small switch-plunger to.

break the signal-circuit.

I have described this invention in the following description as applied to an "overheadswitch for trolley-roads and have so shown it in the drawings; but I do not'restrict my self to its use in such connection nor in, the precise construction shown.

In the accompanying drawings, Figure 1 is a plan of my improveda 'paratus, and Fig. 2 is a central longitudinal section of the device of Fig. 1. i

As shown in the drawings, there is illustrated an overhead switch for a trolley-road for operatin a signal-circuit from a switchblock of insu ation19, upon whichtwo termi: nal contacts 20 are secured in a stepped recess of the block. The block is mounted on a base-plate 30, held on suitable insulators 33, attached to the trolley-wire 29. To the other end of the base-plate 30 there are secured two brackets 34, one on each side of slots 35 in the base-plate. The brackets carry the shaft 27 with depending 'trippingarms 28, freely pivoted thereto and hanging slightly below the trolley-wire 29, so that the trolley-Wheel 31 will strike .the lower end of the depending arms or levers 28 to throw them to one side or the other as. the car passes beneath. There is loosely mounted on the shaft 27 a segment 25, to which one end of an operating-chain '24 is attached. The segment 25 has two'prdjecting lugs 26, extending at right angles to the base-plate Ice and occupying a position over the slots 35 in the same, so that the trolley-pole-when mom ing in the direction shown inthe drawings will strike the arms 28, cause them. to abut;- against the lugs 26 to rotate the segment, and" exert tension on the chain 24. Midway between thelcontact-block 19 and the operating switch-lever and brackets. I mounta pneufmatic transmitting means comprisin -a large cylinder 1, communicating wit a small cyhnder 2, both mounted upon a bracket 3; The large cylinder is provided witha piston-rod 12 forvits of its'plunger c 'es a wedged tripping device:

.711 An outletll is made at one end of the chamber, while an outlet-regulating valve 32 is arranged t-o'communicate with the mid portion of the chamber. Springs 16 16, se-

cured ,to-aucross-hea'd '1 5 on the piston-rod 1 2 serve to normally force the iston or plunger into the position shown in ig.2.' The cylm- *der 2 provided with a plunger-rod 13, carthrough theiblock, so that upon the passage 'of the'blockoverthe contact-stripsZO the than the'springs '16. a On avertical linewith an insulated contact-block 1-8 at its. free end, which may'have suitable -contact levers 2'1 mounted'on a shaft '23, passing circuit will be closed to any desired electrical apparatus. -A cross' head 36, fast to the P un er-rod" 13 ,is connected by s rings v17-to suita le'lu s on the outside of t e cylinder-' casing. T e springs .17 are ofless strength the inner position of the wedged tripping .de-

' vice? I provide a' .charnber 4, having open,

ings 10 to the cylinder'jl and having an outlet to the atmosphere, In thisfchamber. I provide a let-ofi valve comprisin a valve-body 5 pressed against the opening to the atmosphere by a spring ,8 when the plunger is retracted. The valve preferabl as a three-cornered stem passingthroug the-outlet to the atmos here to make a'free passage to the air. e lowerend of the valve within the cylinder carries'a loop 7 in such position with relation to the tripping wedge that thevalve maybe engaged and held. off its seat when the device is in the po-" sition of'Fig. 2. v I 1 I p In operation when the trolley-wheel 31 strikes the depending arms 28 it throws the segment 25'to the leftof Fig.2 to pull the plunger '12 out: against the action of the springs, 16, and when'the wheel leaves the armsl2'8the springs will tend to return the piston, compressing the air within the cylinder 2 and-throwing the contact-block 18 to the right to make contact. The piston 12 will travel inward slowly in comparison to the mcnt of the contact-piston, because of ger diameter. Its time of travel will be elated by the throttle-valve 32, so that a in a I slaslnpot action will be secured (llll'lDQI the plunger, which is secured to this pain 24, whi e the other end a spring-operated aid-transmitting device a stem 6,

inward. travel of the piston during su'bstantially the entire inwardtravel of which the contact block will be in connection with the 7, draw the valve- 5 downard against ts spring and open the 'twocylinde'rs to theatmosphere, allowm the piston 13'to rapidly be drawn back to t e position shown by the spring 17, inwhich position the device will beready for another operation. These springs 17 may act to limit the outer movestrips. When the, plunger reaches the posie "ti-on. shown in Fig. 2,-its'w'ed'ge will engagethe loop ment of the iston 13', though other; means may obvious y be used. a It'will be noted that a trolley-wheel traveling'in the opposite direction on the wire will have no e ect upon the arms 28, except j to idlyioscillate them, and that a car standing" 'in position with its wheel against the levers 28 will be able to send no signal until the le-' vers are released bythe' wheel loose chain 24. A

What. I claim as my. invention-is- 1.. A switch, an -o eratingdevicetherefor,

inyiew-ot the operation of the'switch-armby the transmitger connected to said arm, and acylin er in which it maybe reciprocated .to be withdrawn by-s'aid arm, and sprin means tore-'- tract said plun er u on its re ease, imau-tomatic let-cit va ve a apted-to be engaged by said plunger toward the end of its stro; e.

3. A switch, an operating-arm therefor, a Y

.springoperated fluid transmitting device between them, said device comprising a lun ger connected-to said- ;arm, and a cyli er inwhich it may be reciprocated, sa d switch comprising a P y n therefore? i eratively connected with said first cylinder, an automatic let-ofi valve adapted for opera-- tion after the transmittingof the motion of the operating-arm 'to the switch-arm.v

4, A'switc'h, an o crating-arm therefor-, a spring-operatedflui -tra-nsmitting device between' them, said devicecompris'i'nga lun-- ger connectedto said, arm, and a cylin er in 4 which it may be reciprocated, anautomatic let-ofi valveada ted to be engaged by said plunger toward t eend of its stroke.

5. In combination with a conductor, an

insulated support therefor, a structure carried on said support comprising two ch'am- V hers intercommunicatmg with each other, a i

vent to the interior ofsaid chambers, a piston in one chamber, a contact-block carried thereby, a second contact-block carried-on I said support, and adapted to be operativelyengaged and dis engaged by the contact block of the plunger, a piston in the other chamber, an operating-arm freely pivoted on said support and engaged by a flexible con- Sighed at New York, N. Y,., this 19th day of April, 1906.

1 WILLIAM R. THOMPSON.

Witnesses;

EMERSON R. NEWELL, BEATRICE MIRVIs. 

